\section{Introduction}

The controllers presented in this work were evaluated in simulation, using a model based on a two-compressor system at an ABB Research Facility. 
The physical setup is described in \cite{Cortinovis2015} for a single compressor.
The simulations were performed using the Dormand-Prince adaptive step-size algorithm for numerical integration of the state equations and implemented in both \mlab{}/\slink{} and \cpp{} (see \sect{mpc:implementation}).
In order to isolate the effects of changing controller types and parameters, the model was kept as simple as possible and the two compressors were assumed to be identical.
Two different configurations were tested: a parallel configuration and a serial configuration, described in further detail below.


